Appendix A-5

Biomedical Research

These are selected biomedical findings, not an all-inclusive list. Results are noted only under the first flight program in which they were found, except when significantly modified by data from subsequent flights. Thus, although weight loss was observed after every flight, it is mentioned here for the first flight program and then, when modified by longer duration, for the last.

Early 1960s: Mercury, Vostok

Considerable weight loss of 3.5 kg (8 pounds) postflight.

12 percent increase in heart rate, normalizing after 9 to 19 hours.

Mid-1960s: Gemini, Voskhod

Decreased capacity to work postflight.

12 to 15 percent decrease in bone density; bone decomposition potentially dangerous.

Heart rate as high as 180 beats per minute during extravehicular activity.

Blood abnormalities:
- Loss of red cells and plasma volume.
- Decrease in important electrolytes (sodium, potassium). - Changes in hormone levels.

Abnormalities in urinary excretion: - Progressively increasing calcium loss. - Increased nitrogen, aldosterone, and catacholamines. - Reduced sodium and chlorine post flight.

Late 1960s - Early 1970s: Apollo,Soyuz

Adaptation to weightlessness; high work capacity inflight, but significantly lower capacity postflight; two weeks needed to recover.

Muscle atrophy:
- Decreased strength, reflexes, and size of muscle.
- Variable complaints of muscle pain inflight and up to five days postflight.

Cardiovascular and hemodynamic adaptation:
- Decreased cardiac size and output.
- Reduced blood pressure postflight.
- Decline postflight in orthostatic tolerance (ability to stand without fainting).

Unpredictable incidence of motion sickness, vomiting,
and/or tumbling sensations; on occasion, functionally

Changes in quality (types, viability) and quantity of bacteria normally associated with Man; significant implications for epidemiology of diseases, immunity, and digestion.

Observations of visual light flashes by all crew members, resulting from the impact of cosmic rays.

Mid to Late 1970s: Skylab, Salyut

Decreased rate of weight loss with increased flight duration; pattern of weight loss indicative of early fluid loss and later tissue loss.

Roughly half the body volume loss occurred in the legs alone.

Shift of blood toward head region early inflight, contributing to a sensation of fullness in the head that persisted throughout flight.

Leg muscle atrophy; little or no change in sizes of arms and chest.

Rigorous inflight exercises were successful in facilitating recovery post flight.

No mineral loss in upper extremities, although significant loss in heel bone after 84-day flight.

Postflight reduction in cardiac output and stroke volume and increase in heart rate.

Red cell mass loss during first 30 days, but gradual recovery after 60 days. Thus, decrease in red cell mass im mediately after 84-day flight was approximately one-half that of earlier (28-day and 59-day) Skylab flights.

Decreases in various enzymes in volved in red blood cell metabolism.

Elevated white blood cell levels in flight, with rapid recovery postflight. Also, slight changes in humoral im munoglobulins.

Sensory changes, including slightly decreased visual acuity and depth perception postflight and differences in taste of food samples between in flight and postflight periods.

Postflight impairment of coordination and balance with eyes closed, although fairly normal with eyes open; implications for vestibular adaptation involving reliance on visual sensory input.

Level of overall microbial contamination greater in 84-day flight than in previous flights, mostly due to increased population of fungi; implications for environmental control of future long-duration missions.

one astonaut upside down balancing on the finger of another in the Skylab
A headstand in space: demonstrating weightlessness in Skylab.

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